An oxide thin-film transistor mainly includes a gate electrode, an oxide semi-conductor layer, a source electrode and a drain electrode. In order to enhance ohmic contact between the source electrode and the oxide semi-conductor layer and ohmic contact between the drain electrode and the oxide semi-conductor layer, a plasma treatment process is employed so as to convert two boundary regions of the oxide semi-conductor layer in contact with the source electrode and the drain electrode into conductors. The plasma treatment process is mainly used to enhance, using a plasma, the plasma environment of a plasma enhanced chemical vapor deposition (PECVD) equipment or a dry etch equipment, for example, a plasma of. e.g., helium (He) gas, argon (Ar) gas or sulfur hexafluoride (SF6) gas is used to convert two boundary regions of the oxide semiconductor layer in contact with the source electrode and the drain electrode into conductors.
However, other layers of the thin-film transistor would be damaged by the plasma treatment process, such that performance of the thin-film transistor is affected. In addition, a reversible change is prone to occur to a conductor obtained through a plasma treatment process, such conductor may be restored to a semi-conductor, and the thin-film transistor may be out of function.